Blind stitch attachment



June 16,

BLIND STITCH ATTACHMENT CARP Filed Feb. 9, 1962 [NVENTOR ARTHUR CARP ATTORNEYS United States Patent O 3,137,255 BLIND STE'ICH ATTACHMENT Arthur Carp, 6220 Northwood, St. Louis, Mo. Filed Feb. 9, 1962, Ser. No. 172,159 7 Claims. (Cl. 112-140) l fault in prevailing blind stitch attachments which is the failure of such devices to cope satisfactorily with cross seams or other irregularities, and which have a tendency to skip stitches whenencountering conditions of thatkind. An object of this invention is to provide an attachment which will function continuously smoothly and uniformly on work of varying thickness.

Yet another object is achieved in the provision of an improved attachment of the character described which is suitable for machines vof both the regular, rectilinear needle movement, and also those wherein the needle moves in a zig-zag pattern.

These and other objects and advantages will be explained in the following description of the invention wherein reference is made tothe accompanying drawing illustrating a practical embodiment.

In the drawing:

FIG. 1 is a side elevational view showing the attachment of the present invention mounted on the presser bar of the machine and showing the general relationship thereof with the needle bar and needle;

FIG. 2 is a front elevational view of the assembly illustrated in FIG. l;

FIG. 3 is a plan view of the attachment shown partly in section, the sections being taken at line 3-3 of FIG. 1;.

FIG. 4 is a fragmentary plan view showing the attachment as operating on a piece of folded material in the region of a transverse seam, taken on line 4--4 of FIG. 1, Vand FIG. 5 is a vertical sectional view through the attachment, taken at line 5-5 of FIG. l, illustrating the operating relationship of the device and needle with the material being stitched.

Generally described, the attachment of the present invention comprises a bracket 1 which is adjustably` mounted, by means to be hereinafter described, to the presser bar 2 of a conventional sewing machine. The attachment includes a presser foot indicated generally at 3, and a gauge indicated generally at 4. Gauge 4 serves to position and guide the material or work piece designated 5, with respect to the needle 6, shown mounted on the needle bar 7 of the sewing machine.

As with prevailing blind stitch attachments stitching is performed along a fold in the work piece, the fold being such as to bring the wrong or inner side of the material outermost for presentation to the needle along the fold line. In FIG. 5 the material is arranged for blind stitching a hem. The material is folded at 8, and doubled back at 8a a distance equal to the width of the hem. Stitching along the fold line 8 is made to the underlying ply 9. It is desirable to guide the material that the needle will catch to the material at the extreme edge of the fold 8, thus to leave only a pin point of thread showing on the right side when fold 8 is opened out. The guiding and holding the material with respect to the needle so as to accomplish this purpose is the function of gauge 4.

ice

Bracket 1 is angulate in form, and includes an upper portion 10 that extends horizontally behind the vertical presser bar 2 and is attached to that member through the agency of a thumbscrew 11 and an L-shaped strap 12, as best appears from FIG. 3. The strap 12 is rigidly secured against flattened surfaces of the presser foot bar by a screw 13. The thumbscrew 11 is threaded in an aperture in strap 12, and its threaded shank passes through an elongated opening 14 in the upper portion of bracket 1. The described arrangement enables the bracket 1 and parts carried thereby to be adjusted horizontally, or in a direction which is transverse to the stitching direction. A lower portion 44 of bracket 1 has a depending flange 15 extending vertically, parallel with the direction of stitching movement.

The presser foot 3 is pivotally connected to the depending flange 15 by a transverse pin 16 extending through said flange and supported at itsends in a pair of spaced bosses 17 rising from the presser foot proper, near the rear end thereof. As best appears in FIG. 3, the presser foot is provided with an opening or passage 18 for needle 6, and a slot 19 extends forwardly from the needle passage 18 to the front end of the presser foot. The said passage and slot bifurcates the forward end of the presser foot, forming a relatively lesser claw portion 20 having an upturned forward extremity 21, and a relatively greater claw portion 22, also having an upturned forward end 23.

Gauge 4 essentially comprises a relatively thin platelike member which extends generally vertically through the needle passage 18 and slot 19 of the presser foot. A tail portion 25 of the gauge extends into the space between the bosses 17 and the presser foot and is pivotally connected to the mounting bracket 1, preferably by pivot pin 16. By the preferred mounting arrangement described the presser foot 3 and the gauge 4 have a common pivotal axes on mounting bracket 1 but are adapted for independent pivotal movement, one relative to the other.

Chiefly for purposes of strength and rigidity an integral flange 26 extends laterally from upper edges of the plate member 24 and tail portion 25 of the gauge 4. Flange 26 also provides a stop for limiting the extent of its downward movement relative to that of the presser foot, by reason of engagement of flange 26 with the forward upturned end of the lesser claw portion 2t). As appears from FIG. l, the limit of downward movement of the gauge 4 relative to the presser foot 3 is such that the lower edge 27 of the gauge will extend only slightly below the lower surface of the presser foot. Also from FIG. l it will be observed that sloping upper edge portions` produce a recess or valley, indicated at 28, in gauge 4, to accommodate and preclude interference with the needle bar 7 when that member is in its lower-most position.

The plate member 24 projects forwardly a substantial distance beyond the forward end of the greater claw portion 22, terminating, in a curved forward edge `29. A lateral flange or foot oriin 30 projects from the lower forward edge of the gauge piece. The forward edge 35 of this lin is up-tilted, as indicated at 35 to enable it to pass more freely over under-lying material without snagging the same.

With reference to FIGS. 2 and 5 it will appear that gauge 4, and more particularly its plate portion 24, extends at a slight angle to the axis of the needle 6.

Special attention is directed to the provision of a lateral boss or protuberance 31, fomied on the side of plate member 214. The boss 31 is confined within the environs of the needle passage 18. As appears from FIG. 3, forward areas of the boss 31 merge smoothly into the plane of the surface of plate member 24. In vertical aspect, as appears from FIG. 5, the side surface of the boss 31 slopes in general correspondence to the slope of plate member 24. Boss 31 is provided with a recess 32 directly opposite the needle, to accommodate the needle on alternate strokes thereof during a zig-zag stitching operation, well known and understood in the art. In FIG. 5 the broken line showing of the needle illustrates the position thereof in alternate strokes of a zig-zag operation, the needle in such position passing through the recess 32 in the boss 31. In all of the figures the needle 6 is shown in full lines in the normal or regular operating position which, for the production of blind stitches with the use of the device of the present invention, will Vhave its axis closely adjacent the lower surface portion of the boss 31, as appears in FIGS. 3 and 4.

In using the device of the present invention, as for example in stitching a hem of a garment, the marginal portion of the material, designated 9 in FIG. 5, is doubled back, and the material folded or doubled over as at S along the intended stitch line, as heretofore explained. rlhusly arranged, the material is fed into the attachment with the edge of the hem portion 9 underlying the foot or 1in 39 of the gauge piece. The material is fed through the attachment while the foid line S is maintained against the gauge surface of plate portion 24, and most particularly against the boss 3l where actual stitching takes place.

FIG. 4 illustrates the operation of the attachment on material wherein a transverse Seam designated 33 in the material 5 presents an youtstanding shoulder 34 to the gauge 4. Absent the special gauging provisions afforded by the boss 31 an outstanding shoulder produced by` a seam or the like would tend to displace the material immediately forwardly of such shoulder away from the needle and out of its normal path of movement. ln that case, there results in a gap in the line `of stitches in the region of a transverse seam or other thickening of the material. Such condition is precluded in the present invention by the provision of the gauge and guide shoulder of limited extent located closely adjacent the needle, afforded by the boss 31. The iin 3l) with its uptilted forward margin allows the gauge piece 4 to ride smoothly over any transverse seam which it may encounter, without snagging the same.

It will appear that with thick materials the fold line 8 will contact the gauge 4 at a relatively higher level, set back a relatively greater distance from the normal needle axis, this by reason ofthe inclination of the gauge. Hence the needle will desirably have a deeper bite with thick materials than with thin materials.

Having described a practical embodiment of my invention is will be understood that changes may be made in the described device without parting from the spirit sage to the forward end of said presser foot to bifurcate the presser foot, and

(d) a gauge pivoted to said bracket for vertical rocking movement,

(e) said gauge including a plate portion extending through said needle passage and slot, said plate portion being spaced to one side of the normal axis of needle movement and providing a guide surface for material being stitched,

(f) said plate portion projecting beyond the forward end of said presser foot, and having an upwardly curved forward surface to enable said plate portion to ride over a seam or other relatively thick part of the material, and

(g) said plate portion having a laterally projecting protuberance in said needle passage, providing a guide surface of limited area in close proximity to and ahead of the normal axis of needle movement.

` 2. A sewing machine attachment as described in claim l wherein the protuberance on the plate portion of said gauge is provided with a side recess to accommodate the sewing machine needle during zig-zag stitching.

3. A sewing machine attachment as described in claim 1 in which said proturberance is disposed closer to the needle axis than the plate portion immediately ahead of such protuberance to preclude displacement of the material out of the normal path of movement under the needle upon encountering a cross seam or other irregularities.

4. A sewing machine.` attachment as delined in claim l in which the said protuberance projects from one side of the plate portion toward the normal needle axis to provide a guide surface of limited area ahead and behind in close proximity to the normal axis of the needle movement.

5. A sewing machine attachment as deiined in claim 1 in which the protuberance is located closer to the needle axis than the plate portion immediately ahead of such and intendment of the invention set forth in the following claims.

l claim as my invention: l. A sewing machine attachment of the character described comprising:

' (a) a bracket attachable to the presser foot bar of a sewing machine, (b) a presser foot mounted on said bracket, (c) said presser foot having a needle passage and a slot extending longitudinally from said needle pasprotuberance, the protuberance being inclined upwardly and away at a slight angle to the needle axis to accommodate materials for deeper bites corresponding to the thickness of the materials.

6. A sewing machine attachment as dened in claim 5, in which the said plate portion ahead of said protuberance is inclinedupwardly and away ata slight angle to the needle axis.

7. A sewing machine attachment as deiined in claim 1 in which the protuberance projects from one side of the plate portion toward lthe normal needle axis to provide a guide surface of limited area ahead and behind in close proximity to the normal axis of needle movement, the

protuberance being inclined upwardly and away at a s slight angle to the needle axis to accommodate materials for deeper bites corresponding to the thickness of the materials.

References Cited in the file of this patent UNITED VSTATES PATENTS 468,056 Morrison Feb. 2, 1892 2,341,686 Billingtori Feb. 15, 1944 2,573,170 'WiegardtV Oct. 30, 1951 2,699,743 Hill Jan. 18, 1955 

1. A SEWING MACHINE ATTACHMENT OF THE CHARACTER DESCRIBED COMPRISING: (A) A BRACKET ATTACHABLE TO THE PRESSER FOOT BAR OF A SEWING MACHINE, (B) A PRESSER FOOT MOUNTED ON SAID BRACKET, (C) SAID PRESSER FOOT HAVING A NEEDLE PASSAGE AND A SLOT EXTENDING LONGITUDINALLY FROM SAID NEEDLE PASSAGE TO THE FORWARD END OF SAID PRESSER FOOT TO BIFURCATE THE PRESSER FOOT, AND (D) A GAUGE PIVOTED TO SAID BRACKET FOR VERTICAL ROCKING MOVEMENT, (E) SAID GAUGE INCLUDING A PLATE PORTION EXTENDING THROUGH SAID NEEDLE PASSAGE AND SLOT, SAID PLATE PORTION BEING SPACED TO ONE SIDE OF THE NORMAL AXIS OF NEEDLE MOVEMENT AND PROVIDING A GUIDE SURFACE FOR MATERIAL BEING STITCHED, (F) SAID PLATE PORTION PROJECTING BEYOND THE FORWARD END OF SAID PRESSER FOOT, AND HAVING AN UPWARDLY CURVED FORWARD SURFACE TO ENABLE SAID PLATE PORTION TO RIDE OVER A SEAM OR OTHER RELATIVELY THICK PART OF THE MATERIAL, AND (G) SAID PLATE PORTION HAVING A LATERALLY PROJECTING PROTUBERANCE IN SAID NEEDLE PASSAGE, PROVIDING A GUIDE SURFACE OF LIMITED AREA IN CLOSE PROXIMITY TO AND AHEAD OF THE NORMAL AXIS OF NEEDLE MOVEMENT. 